bat读取txt最后一行

Question

我要先进行判断文件是否存在，但似乎有问题，命令实效了，哪里出错了呢
if exist q:\0310-%date:~0,4%%date:~5,2%%date:~8,2%.txt.rpt. for /f "tokens=*" %%i in (q:\0310-%date:~0,4%%date:~5,2%%date:~8,2%.txt.rpt) do set str=%%i do echo 集中开卡结果：%str%>>%date:~0,4%%date:~5,2%%date:~8,2%rpt.txt

Answer 1

要引用在循环中动态赋值的变量，需要开启“延迟扩展”，然后用两个感叹号代替百分号来访问变量，修改并优化如下：
@ECHO OFF
SETLOCAL EnableDelayedExpansion
SET SourceFile=q:\0310-%date:~0,4%%date:~5,2%%date:~8,2%.txt.rpt
SET TargetFile=%date:~0,4%%date:~5,2%%date:~8,2%rpt.txt
if exist %SourceFile% (
for /f "tokens=*" %%i in (%SourceFile%) do (
set str=%%i
echo 集中开卡结果：!str!>>%TargetFile%
)
)
ENDLOCAL